Process for making a concentrated coffee product



Patented July 5, 1932 UNITED STATES PATENT orrlca EUGENE J. LOBAND, OISTATE OOLLEGE, PENNSYLVAIl'IA, ASSIGNOB TO THE rm- SYLVAN IA STATECOLLEGE, OF STATE COLLEGE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIAPROCESS FOR IAKING A CONCENTBATED COFFEE PRODUCT No Drawing. Applicationmed June 13,

gases, an aromatic and essential oils that gave coflee its distinctiveflavor, the results have not been satisfactory in producing an extractwhich, when water is added, accurately reproduce the true coflee flavor.The

group of substances, usually high volatile,

which give coflee its distinctive flavor may be designated cafl'eo Ithas also been proposed to collect the highly volatile gases, such ascafi'eol, which pass off during evaporation, in a solvent, and returnthem .to the concentrated extract.

These processes, however, involve evaporation of the infusion orevaporation of the solvent and present the serious objection that whenany evaporation step is used, the high- 1 volatile essential oils thatgive coffee its avor are lost. It is a very important point in thisinvention that no evaporation step is used.

80 According to this invention, the cofl'ee is treated directly with aliquid which catches and retains the aromatic and volatile oils andflavors of the coffee, and which dissolves the caffeine of the coffee.The liquid used is edible and remains in and forms a part of the cofleeextract. Glycerine or its chemical equivalent is the liquid used.

According to this invention, the ground and roasted coffee beans aretreated directly with anhydrous glycerine, at a suitable temperature,whereby the coffee flavors are taken up and satisfactorily retained inthe glycerine. The cafleol is taken up and retained I by the glycerine.Likewise the caffeine,

1928. Serial No. 285,199.

water is a disadvantage, in that it seems to extract bitter constituentsfrom the coffee or seems to cause the formation of bitter constituents,probably acids, which give an unpleasant flavor to the resultingproduct. This is avoided by the use of anhydrous glycerine.

Furthermore, in ound, roasted cofiee, the cafieol is apparent y presentin a combined state, probably as a glucoside, in which state it is notvolatile. The presence of even a small amount of water tends tohydrolyze this mother substance, which is sometimes termed caffeogen,into caifeol and a carbohydrate; this decomposition is distinctly to beavoided, because the cafl'eol is highly volatile and fugitive. Byoperating under anhydrous conditions, the hydrolysis of the cafl'eogen,with resultant formation and escap eil of cafleol, is avoided.

e present preferred way of carryin out the process is as follows:Freshly groun and preferably freshly roasted coffee is heated with aboutfour times of its weight of commercial glycerine; the drier theglycerine the better. The coffee should not be pulverized, as thisincreases the difliculty of subsequent filtration. The temperature ofthe heating should not exceed 100 C. and the optimum range is from 8090O. This heating is continued from 3-8 hours; for fresh grounds, thisheating is from 5-6 hours; for already treated grounds, (if the countercurrent process is used, as will be described), this heating is from 2-5hours.

This heatin is done under reduced pressure, preferab y under a vacuum ofabout 27 inches of mercury. Such a heating under such a pressure removesthe water, the removal of which is of importance, in order to avoidbitter products in the resulting extract.

The above described heating is preferably device ofany suita le type.

The resulting mixture of coflee and the glycerine extract is now puri dby fil-' tration. This filtration presents some difii' -p culties,because the coffee particles tend to clog the filter, necessi g frequentcleaning; even with ordina grin of the coffee beans, some ver 'e dust isinevitably formed, which is di cult to filter out. The complete removalof all particles of coflee is ry in order to give an extract -which isof flavor and appearance or leam. Also, if such particles are not removthere is a rough taste to the extract.

The filtration is preferably done in two stages: In the first stage, thesolution is filtered by gravity through a mesh screen, which removesabout half of the cofl'ee grounds. In the second stage for the removalof the fine particles, the solution is filtered through a pressurefilter, such as a Sweetland filter, under a pressure of about 10-50pounds per square inch. Other pres sures could be used. If the filterhas metal parts, they should be covered by porcelain or the like. Inorder to aid this filtration, a small amount, about 1% ofh 0 super eel,a commercial product which 1s a highly refined diatomaceous earth, ispreferably added. The filtrate is clear of 0d flavor and good gleam. TheSharp ess supercentrlfuge can be used for this second stage filtration,for the removal of the very fine particles, althou h this is not assatisfactory as the Sweetlan pressure filter.

On account of the viscosity of cold glycerinEi the filtration is done atabout C.-

For the strongest extract, a single lot of lycerine is ap ied tosuccessive batches of h coflee. he product is stron but is relativelywasteful of glycerine an cofiee. A strong extract may also be made byallowing fresh glycerine to act on grounds that have been extractedonce, and then a plying this g1 cerine solution to successive batches offresh coflee. This, however, is not as economical of glycerine andcoffee as the threestage, counter current process which will now bedescribed, and which is the preferred wafilof practicing the invention.

the countercurrentprocess fresh glycerine is introduced into a kettlewhich contains grounds that have already been through two extractions.The resultln extract is then used to treat coflee groun that havealready had one extraction. This product in turn is used in the thirdstage with fresh, coffee. The product resulting from this third stage isthe finished concentrated coflee extract. The cofleeitself'trav- Lesa-n4treatment are extrac'tedwithanextractthathasbeenthrough N the treatment,and finalliare extracted with fresh glicerine. In sue a counter-currentrecess 0 strongest cofiee solution is treated with the strongest, (i. e.the fresh) coflee,

grounds which are almost 7' while the cofiee exhausted are treated withfresh glycerine, which obviously has the greatest solvent power forcoffee and will extract'flavoring matter from the unds which an extractthat alread contains some cofiee will notabsorb. If, or example, threecontainers for the cofiee are used, the fresh glycerine acts on thecoflee ounds which have been twice extracted, an any given batch ofcoffee is extracted three times, first by a lycerine extract which haspassed throug two other batches of coffee, second by aglycerine extractwhich has of coffee and thir by fresh g1 oerine. Four or five morestages may be use if desired.

The counter-current princi le is preferably carried out by changing t eflow of the glycerine, without actually changing the cofee grounds fromone tank to another.

The concentrated extract thus prepared is readily soluble in hot water,and at a dilution of 1 to 20 with hot water gives a solutionsubstantially identical with the ordinary coffee beverage. The extractmay also be used as a flavor for ice cream, chewing gum, candy, cake andother food roducts.

The grounds whic have been extracted as described still containconsiderable glycerine adherent thereto and it is of importance torecover this glycerine from the grounds before the are discarded. Thisrecovery is effected y washing the grounds with water and filtering; thesolution is then evaporated at a low temperature, under a vacuum ofabout 26 inches of mercury, which removes the water. The glycerineextract remaining is mixed with fresh glycerine and used in furtherextraction.

The use of glycerine for extracting the coffee flavors is of particularadvantage, because it is not a solvent for fats, and so it does notremove fats from the coffee beans.

assed through one batch Since fats tend to become rancid,-it is ofimportance to avoid the presence of fats in the resulting extract.The-resulting extract therefore, contains no fats and is toxic tobacteria, hence the keeping qualities of the extract are good.

The term glycerineas used in the claims, is intended to cover thechemical equivalents of glycerine.

The 'procem described may be used with satisfactory results in coffeeswhich have been previously treated to remove the cafieine.

I claim as my invention:

1. The process of preparing a concentrated soluble cofiee extractcompris' heating ground roasted cofiee lleans with a ut four times theirweight of anh drous glycerine, at about -8090 C., and tering at anelevated temperature. x 2. The process of preparing a concen tratedsoluble coflt'ee extract comprising heatin ground, roasted cofl'ee inthe resence of a ydrous glycerine under a artial vacuum.

3. The process as claimed in the preceding claim, where the amount ofanhydrous glycerine used is about four times the weight of the coffee.

In testimony whereof I hereunto afiizr my signature. I

EUGENE J. LORAND.

